Even though the name sounds French, the Pensee is an English five line (quintet) syllabic poem, with variable length lines, and no rhyme scheme. The line lengths are as follows:

Line 1: 2 syllables
Line 2: 4 syllables
Line 3: 7 syllables
Line 4: 8 syllables
Line 5: 6 syllables

Further research shows that some sources claim not only the required syllable counts but there is a pattern also.

Line 1: Subject
Line 2: Description
Line 3: Action
Line 4: Setting
Line 5: Final Thought

Line 1: Subject (2 syllables)
Line 2: Description (4 syllables)
Line 3: Action (7 syllables)
Line 4: Setting (8 syllables)
Line 5: Final Thought (6 syllables)

Example:

Book Room
Filled with great thoughts
Floating on happy pages
Last door at the end of the hall
Wonderful library!